Monday, February 09, 2009

Consistence problem of string theory

The understanding, why formal theories, like string theory cannot lead to some particular solution is quite easy in AWT, if we use water surface model for illustration of Lorentz invariance. Beneath water surface the surface wave cannot spread by causal way. With respect to such wave spreading, underwater appears like void and empty space, while such environment definitely exists from more general perspective of some faster reference interaction. For example the motion of surface waves can be followed and observed easily by using of underwater sound waves, i.e. by using of sonar, because sound waves are spreading approximately 1000 x faster through underwater, then the surface waves.

As we can see, the fact, we cannot observe the (motion / reference frame) of environment by its own waves doesn't mean, this environment cannot exist from more distant (nonlocal) perspective. The explanation of wave character of light and many its properties would require us to believe in hypothetical environment for light wave spreading, although such environment cannot be detected by using of light directly.

The existence of such environment is related to existence of so called hidden dimensions of space-time. For real life example, surface waves are spreading along two-dimensional density gradient, which is forming water surface. While underwater is three dimensional environment. AWT explains the existence of surface gradient by compactification of it.

String theory considers as well, hidden dimensions of space-time are somehow compacted. While this assumption is consistent with Aether concept, I newer find an explanation of that claim in string theory literature, the illustration of it the less. It's evident, string theorists somehow guessed it or borrowed this explanation from particle environment concept unconsciously, while ignoring the rest of connections. The punishment was undeniable.

The existence of Aether corresponds the existence of hidden dimensions for surface waves, because underwater space exhibits an additional dimension, with respect to surface. Therefore every theory (like string theory), which is postulating existence of such additional dimensions is postulating the existence of some hidden environment as well - despite the fact, some proponents of these theories doesn't realize it apparently. Hidden dimensions for energy spreading through vacuum are equivalent the underwater dimensions for waves at water surface.

From AWT follows, Lorentz invariance is a result of strictly local perspective, every nonlocal perspective would violate Lorentz invariance, because such violation is just, what the existence of hidden dimensions means. In real life example, surface waves are dragged by underwater whenever we can consider the existence of such underwater, which becomes a reference frame.
Such conclusion makes string theory deeply inconsistent conceptually. It tries to prove the existence of hidden dimensions on background of Lorentz invariance, which is violating them. This is a simple consequence of fact, string theory proponents didn't understood the subject of their own research, trying to replace the understanding by formal regression of reality based on formal postulates and ideas, collected blindly from another theories.

No wonder, resulting theory has no meaningful solution, because it's based on assumptions, which are mutually contradicting each other from their very beginning for most of nonlocal perspectives (if not all). Instead of this, it leads to huge landcape of nearly infinite number of solutions, thus serving like ineffective and quite costly random number generator. String theorists can only hope, for some limited volume and nontrivial space-time topology the effects of Lorentz invariance will compensate the effects of hidden dimensions - but this is not exact just the approach, which we could expect from proclamativelly strictly rigorous physical theory.

Despite of this, many string theorists are apparently quite proud to their formal approach, tirelessly filling publications by various complex equations. I can tell you, today it's nearly impossible to publish string theory article in peer reviewed press without some formal equations. But for laymans should be warning the fact, we never met with some graphics representation or simulations of their results from obvious reasons - simply because such simulations can never exist! Their equations were be never solved explicitelly, neither plotted in their rigorous formal state. Believe it or not - even after forty years of intensive development nobody has seen even single one example of string modeled by string theory - only some pathetic hand-drawn illustrations copied from first textbooks. And we are talking just about numerical models by now, not about some testable predictions, relevant for physics. But string theorists somehow managed their situation for whole long forty years like alchemists of medieval era, promising Philosopher's stone (Lapis philosophorum) for the rest of society.

Isn't it amazing? I can assure you, this is a true real story of contemporary physics.

Unfortunately, as deeper analysis reveals, other formal theories like LQG theory suffers the same conceptual problems, just in less apparent way - as we can illustrate later. The frontier status of string theory only makes it's internal inconsistency more apparent, that's all. This is partially because string theory is based on special relativity, which is easier to comprehend - then more advanced postulates of general relativity, used in other quantum gravity theories.

The optimist sees the doughnut. Pessimist sees the hole in doughnut. Popper's methodology is apparently based on pessimist approach - it requires us rather doubt then to believe and to see the holes in every theory first. Beauty is always somewhat impractical an violated in symmetry - this is what makes it attractive. From single postulate we cannot construct a vector of logical implication. The theory based on fully consistent postulate set would become tautology undeniably. We could derive each postulate from another, thus effectively decrease their count to single one, after then. Therefore no formal math based theory can be completely selfconsistent and as such correct more, then observable reality.

Someone is saying, string theory is beauty and elegant theory. By my opinion, its product of complexity and predictability is suboptimal, as we have a more powerful formal theories already, like the ingenious Heim theory, which handles the concept of hidden dimensions as well, if not better. This doesn't change the fact, every theory brings a new perspectives into our understanding of reality and string theory is no exception. Anyway, from AWT follows, every theory, which expects Lorentz invariance and hidden dimensions at the same moment remains deeply inconsistent, simply because hidden dimensions manifest itself just by Lorentz invariance violation.

67 comments:

The latest Forbes magazine has an article entitled String Theory Skeptic. From long-term perspective the approach based on mutual reconcilliation of relevant aspects of existing theories - rather than denial of them - appears to be more perspective.

(º|º) David Gross a proponent of string theory and Nobel laureate showed a slide where he had written (At 31:30 of this video ):

'The vacua of string theory are all metastable, most uncontrollable, and none constitute a consistent cosmology'...WE STILL DO NOT KNOW WHAT STRING THEORY IS!"String Theory" is a framework --not a definitive theory.

The causes of the inconsistency of String Theory have nothing to do with this statement:

'Anyway, from AWT follows, every theory, which expects Lorentz invariance and hidden dimensions at the same moment remains deeply inconsistent, simply because hidden dimensions manifest itself just by Lorentz invariance violation.'

Don't you know that there are models with hidden dimensions that use the string theory paradigm and do explain the Lorentz symmetry violation?

It has been suggested that energetic photons propagating in vacuo should experience a non-trivial refractive index due to the foamy structure of space–time induced by quantum-gravitational fluctuations. The sensitivity of recent astrophysical observations, particularly of AGN Mk501 by the MAGIC Collaboration, approaches the Planck scale for a refractive index depending linearly on the photon energy. We present here a new derivation of this quantum-gravitational vacuum refraction index, based on a stringy analogue of the interaction of a photon with internal degrees of freedom in a conventional medium. We model the space–time foam as a gas of D-particles in the bulk space–time of a higher-dimensional cosmology where the observable Universe is a D3-brane. The interaction of an open string representing a photon with a D-particle stretches and excites the string, which subsequently decays and re-emits the photon with a time delay that increases linearly with the photon energy and is related to stringy uncertainty principles. We relate this derivation to other descriptions of the quantum-gravitational refractive index in vacuo.

In string theory particles are formed by strings. "Stringy foam" model of space-time basically says, vacuum is composed of stringy particles, thus becoming sort of LQG theory or even 1D Aether theory and as such it can predict Lorentz symmetry violation, because it has nothing much to do with string theory in its original sense. Note that if CMB photons are violating Lorentz symmetry by dispersion of another photons, they can be considered as a "strings" effectivelly and as a tangible evidence of string existence.

I'm upset with you, again. Lubos has tricked to you. Don't you know, Zephir, that D-Branes and open strings have nothing to do with LQG?. I'm not going to discuss AWT, because I only want to discuss the serious/accepted theories at this comment. I'm sorry, but AWT is a lot of idiocy, many nonsense, one after the other, and delete this comment if you want, I've had enough of this, so I'm going to write the true.

Why don't you believe me? I say that it's posible to build up models using the string theory paradigm that violate the Lorentz symmetry. I've quoted a paper whose authors are very prestigious theoretical physicists (much more prestigious than Lubos). Let me remind what is wrote in the Wikipedia Article about Ellis:

In 2004 a SPIRES survey ranked him as the second most-cited theoretical physicist. His publications include one paper with over 1000 citations, six more with over 500 citations, and 104 other papers with at least 100 citations each.

He has over 33,000 citations, placing him as the fourth most cited High Energy Physicist of all time, according to the 2001 and 2004 census

And the least prestigous of the three (nevertheless, very prestigous, too) is Mavromatos, who has got many papers and many citations, as well.

And you wrote that this model is based on LQG, WTF?. If you aren't convinced yet, let me to quote another paper (Lorentz Invariance Violation From String Theory) of the third autor where it's explicity stated:

Although classical general relativity entails Lorentz invariance locally, and the latter symmetry survived many stringent experimental tests, especially the ones making use of high energy particle probes [1], this symmetry may not be a true feature of Quantum Gravity. In this talk I will discuss some instances in string theory where Lonretz symmetry could be broken

/*...AWT is a lot of idiocy, many nonsense, one after the other...*/So far you didn't object any such nonsense. My last explanation of Magnus effect was left without comment - so I can suppose, you've nothing to say about/against it.

/*..I say that it's possible to build up models using the string theory paradigm that violate the Lorentz symmetry...*/...and one of string theory paradigms is Lorentz symmetry - or not?

Of course, string theory is using dosens of various postulates, so if you omit LS, you can still derive something, which has "something to do" with string theory - but such approach is not rigorous approach. My point is, every theory is defined by its postulate set and if you use a different/reduced postulate set, you're basically working with different theory.

/*.. some instances in string theory where Lorentz symmetry could be broken..*/

But what does it mean "instance of string theory" here? Such instance is definitely not inherited from string theory, which is inherited from special relativity theory, which is inherited from Lorentz symmetry postulate.

With such approach we could propose an "instance" of LQG theory, which doesn't contain some loops at all, for example...;-) With such approach we could derive virtually whatever theory of our personal preference under name "string theory" just for keeping grant support and/or interest of specialized journals. This is indeed not very ethical approach, rigorous the less. We cannot derive 1 = 2 by using of rigorous theory, which considers 1 = 1 without breaking causality in some step of derivation.

Sorry, I've lost my head, I was furious because I felt that you were not believing to me, however you were believing all stuff that Lubos has written. Indeed sometimes, I see something of consistency in AWT, at least intuitively. But, I know that AWT is an intuition of yours, that points toward Bohm mechanics and toward this this theory of gravity, where the gravity arises from a superfluid that is made up of neutrinos. Namely, the aether is not more than a superfluid. From this superfluid we can obtain all forces and all particles. We must study the dynamics of the superfluids if we want to understand the aether. In order to achieve this task, I've bought this book to study it carefully. Although, the hidden dimensions are not necessary.

String Theory is not a theory but rather a paradigm. You can build up many models using the string theory framework. Some models are indeed Lorentz invariant but other present a mechanism that breaks the Lorentz symmetry. Lubos always speaks about the latter. But you can read the following sentence at the very beginning of the Wikipedia's article:

String theory itself comes in many different formulations, each one with a different mathematical structure, and each best describing different physical circumstances.

So, you can change the math and you can obtain other model based on strings which is very different to the existing models. In the paper of the third author is said at the abstract:

I pay attention to explaining the appearance of bi-metric models from such string theories, which could serve as examples of alternative scenaria to dark matter.

Even though, Lubos had written a post where he wrote that bimetric theories are pseudoscientific. You can see clearly the supersymmetric behaviour of Lubos Motl, here.

Returning to the quoted paper, the author shows that one thing is the covariance of the world-sheet and another thing it's to construct a model where the speed of photons are energy dependent. The picture is very simple:

Let's supose that the universe is formed by a 10-D space, but we are living in a 3D-Brane. The photons are open strings. The problem is that the 3D-Branes are not perfect. They have some defects. These defects can be considered like particles, and we will call them D-particles. The open strings can interact with the D-particles. When the open string interacts with a D-particle, then an intermediate composite state is formed. This state is a string-D-particle state. The string-D-particle state lives an uncertainly time interval dt. In order to maintain the energy-momentum conservation and due to the recoil is produced a distortion in the space-time that surrounding the composite state. This mechanism produces a change in the metric, i.e., a bimetric theory from a string theory model. A bimetric theory is equivalent to a theory which has lost the Lorentz symmetry as it's perfectly stated at the Wikipedia's article:

Bimetric theory refers to a class of modified theories of gravity in which two metric tensors are used instead of one. Often the second metric is introduced at high energies, with the implication that the speed of light may be energy dependent.

/*..however you were believing all stuff that Lubos has written..*/From where you got such idea? I can't believe it again...;-)

/*..When the open string interacts with a D-particle, then an intermediate composite string-D-particle state is formed, which lives an uncertainly time interval dt ..while it produces a distortion in the space-time that surrounding the composite state....*/This is just physmatical description of the well known process: photons of gamma radiation can materialize with CMB photons temporarily under production of metastable particle-antiparticle pairs, which can spread in subluminal speed only, thus increasing dimensionality of space-time with respect to light spreading. Nothing strange is about it, but the space-time filled by CMB photons isn't exactly 3.00000 D space, so that Lorentz invariance postulate of string theory cannot be applied on it anymore.

/*..often the second metric is introduced at high energies, with the implication that the speed of light may be energy dependent...*/Indeed, you can introduce arbitrary number of ad-hoced metrics in such a way, string theory will change into LQG effectively - but such extension isn't part of string theory in its original definition.

I can imagine, Motl isn't very happy about it in similar whay, like me, when Sean M. Carroll writes about vector field and he calls it "aether". This is indeed BS: vector field is just a vector field and not Aether.

The violation of LS is equivalent to direct observation of Aether, which is indeed impossible from geometry reasons (we cannot observe environment by its own transversal waves). So we cannot break Lorentz symmetry of space-time as such, but we can consider spreading of energy via longitudinal waves through extradimensions, which increases space-time dimensionality temporarily. Because longitudinal waves are gravitational ones, the CMB photons are manifestation of gravitational waves at the same moment. Note that portion of energy violating LS cannot serve for propagation of information at distance, for example photons in solitons can spread in single wave packet, but they're scrambled perfectly during their travel.

Gauss's Theorema Egregium (Latin: "Remarkable Theorem") is a foundational result in differential geometry proved by Carl Friedrich Gauss that concerns the curvature of surfaces. Informally, the theorem says that the Gaussian curvature of a surface can be determined entirely by measuring angles and distances on the surface itself, without further reference to the particular way in which the surface is situated in the ambient 3-dimensional Euclidean space. Thus the Gaussian curvature is an intrinsic invariant of a surface

Zephir, How many times I have to tell to you that you should study math? So we can break the Lorentz symmetry and observing the aether if AWT was correct.

/*...we cannot observe environment by its own transversal waves...*/It should be added "..at the same time", i.e. locally. Non-locally Lorentz symmetry can be indeed violated - but this is not, what a strictly local special relativity is about.

Non-locally we can measure angles in triangles of finite size without problems.

/*..so we can break the Lorentz symmetry and observing the aether if AWT was correct...*/In AWT Aether is environment of infinite mass/energy so it cannot be observed by observer of finite mass/energy density.

There's is another theorem: "Simillia simillibus observatur." i.e. "Only similar things can interact mutually in observation". Aether is just an abstract emergent principle from this perspective in similar way, like "space" or "time" concepts. It just says, every objects is composed of many other objects. If these objects are hot and/or massive, then the child objects must be hot and massive too. It doesn't says, some most fundamental objects exists or remain observable.

In fact, here exists a geometrical limits in observability of most fundamental particles from particular level of Aether hierarchy and we can deduce, only few closed members of mutual hierarchy can be observed directly as a hyperspherical particles in space-time of limited number of dimensions.

You know a lot more than I had imagined. This experiment didn't rule out special relativity. But special relativity also say that the aether doesn't exist. So, why are you defending so bizarre viewpoints?

Any professor of theoretical physics, who holds a chair, would expel you of his department if he heard you to speak about AWT as serious candidate for a TOE.

"Einstein's elegant solution was to discard the notion of an aether and an absolute state of rest."

... but I don't see any objective reason for doing this. Can you propose some?

A professor, who holds a chair, is usually the chief of the academic department. And you have to comply with his desideratum. If you don't make it, he will have any problem for expelling you. When a professor speaks, then you must shut up, otherwise, he will get angry with you and you will be sorry. If a professor say that AWT is a piece of crap, then the case is closed. No word more about this stuff. The problem is over. A professor is like a bishop, it is not permissible to interrupt him in the middle of the sermon. If you thinks he's wrong the best thing you can do is to shut up.

/*...your problem Zephir is that you are following the wrong way...*/Yep - everybody "knows", AWT is wrong way - but nobody can say me, why. Discussions about AWT with you reminds me of Bohr's cautionary tale of the farmer with the horseshoe over his barn door.

His neighbor: "You don't believe in that, do you?"Bohr: "No, but my friends tell me you don't have to believe in it for it to work."

Certainly, a pretty smart exposition about this controverted topic done by a nice guy. If you or any of the readers of AWT have a minute I strongly recommend reading this lucid post. Only a flaw, the post has a link with the blog of Peter Woit, a rascal who is using the fall of string theory to make money for his own profit.

ElCid, I never said this - I'm just explaining the insintric inconsistency of string theory, which leads to landscape of solutions and which is out of discussion.

It's mainly of concentration of money, what makes string theory so interesting for various theorists.

Many formal concepts developed in context of string theory (but implemented in another theories, too - like the AdS/CFT duality, supersymmetry, etc..) appears quite OK from perspective of any other theory, including AWT. And I've nothing against concept of extradimensions (althought it's missunderstood heavily with string theorists).

Here's another take on this announcement. Author has no idea how this paper is supposed to contain a "test" of string theory.... http://www.math.columbia.edu/~woit/wordpress/?p=3127 String theory considers constant speed of light and existence of extra-dimensions, which will manifest just with violation of constant speed of light. The confirmation of one of postulates will render the second one unusable.

String Theory has many aspects of theology, except the need for a belief in a creator. It has made no realistically testable predictions that other hypotheses cannot make (like a religion), its proponents believe that non-believers are heretics (like a religion), it is claimed to be infallible yet is full of inconsistencies (like a religion), when aspects of it are proved to be untrue, they morph to match (god of the gaps). In fact, to call it a theory misuses the term in the same way as creationists who disparage evolution as "just a theory"

In Issue of Nature, March 1, 2007, Clive Speake wrote about another prediction of String Theory made by Sundrum[R. Sundrum, Phys. Rev. D 69, 044014 (2004).]. In it, graviton is a "fat string", with a spatial scale associated with it at 90 microns. This means that the good old Newton's gravitational constant is expected to deviate from its standard value below 90 microns. A recent measurement of the gravitational constant made by Kapner et al.[2] have measured the gravitational constant up to 55 microns, with no deviation from the expected value [D.J. Kapner, et al. Phys. Rev. Lett. 98, 021101 (2007)]

Paul Davies, in his Op-Ed piece Taking Science on Faith, uses recent untestable speculation about multiple universes motivated by string theory to claim that “the mood has now shifted considerably” among physicists. He characterizes physics as being, just like religion, “founded on faith”, faith in the existence of intelligible laws describing nature and in a “huge ensemble of unseen universes”, the so-called “multiverse”.

The string theory inconsistency did manifest recently during superluminal neutrino observation at the OPERA experiment, which could be explained with extradimensions of string theory, but it would violate another postulates, on which string theory is based, i.e. the invariance of speed of light.

In The Trouble With Physics, Lee Smolin takes us on a journey through the history and science of physics and identifies this sociological division as the heart of the eponymous trouble: string theory is a theoretical field being explored by scientists with a particle mindset. 25 years and 11 dimensions later, no such luck. Smolin gives string theory full marks for addressing problem three, an incomplete on problem one and a failing grade on the other three.

scientificamerican.com: Is Supersymmetry Dead? The grand scheme, a stepping-stone to string theory, is still high on physicists' wish lists. But if no solid evidence surfaces soon, it could begin to have a serious PR problem

Lorentz Violation in Extra Dimensions "In theories with extra dimensions it is well known that the Lorentz invariance of the $D=4+n$-dimensional spacetime is lost due to the compactified nature of the $n$ dimensions leaving invariance only in 4d".

String theory can never lead into testable prediction, because it considers extradimensions and Lorentz symmetry, whereas the extradimensions will manifest itself just with Lorentz symmetry violation.Most string theorists insist that string theory does not violate equivalence principle. However in papers by Thibault Damour and Cliff Will they point out string theory contains dilaton fields which violate equivalence principle. This is another contradition.In Verlinde’s colloquium on entropic gravity at Caltech last semester, he claimed entropic gravity follows from string theory and it explains MOND. OTOH almost all string theorists believe that “particle” dark matter exists and follows from string theory.In Petr Horava’s colloquium at Berkeley on Horava-Lifshitz gravity (which is archived on video), he mentioned that this is a consequence of string theory. But Witten and many other string theorists thinks that this theory is wrong. So again another contradition.

What experiment would disprove string theory?By detecting Lorentz violation at high energies: string theory predicts that the Lorentz symmetry is exact at any energy scale; recent experiments by the Fermi satellite and others have showed that the Lorentz symmetry works even at the Planck scale with a precision much better than 100% and the accuracy may improve in the near future; for example, if an experiment ever claimed that a particle is moving faster than light, string theory predicts that an error will be found in that experimentBy detecting a violation of the equivalence principle; it's been tested with the relative accuracy of and it's unlikely that a violation will occur; string theory predicts that the law is exactBy detecting a mathematical inconsistency in our world, for example that can be equal both to as well as ; such an observation would make the existing alternatives of string theory conceivable alternatives because all of them are mathematically inconsistent as theories of gravity; clearly, nothing of the sort will occur; also, one could find out a previously unknown mathematical inconsistency of string theory - even this seems extremely unlikely after the neverending successful testsBy experimentally proving that the information is lost in the black holes, or anything else that contradicts general properties of quantum gravity as predicted by string theory, e.g. that the high center-of-mass-energy regime is dominated by black hole production and/or that the black holes have the right entropy; string theory implies that the information is preserved in any processes in the asymptotical Minkowski space, including the Hawking radiation, and confirms the Hawking-Bekenstein claims as the right semiclassical approximation; obviously, you also disprove string theory by proving that gravitons don't exist; if you could prove that gravity is an entropic force, it would therefore rule out string theory as well

By experimentally proving that the world doesn't contain gravity, fermions, or isn't described by quantum field theories at low energies; or that the general postulates of quantum mechanics don't work; string theory predicts that these approximations work and the postulates of quantum mechanics are exactly valid while the alternatives of string theory predict that nothing like the Standard Model etc. is possibleBy experimentally showing that the real world contradicts some of the general features predicted by all string vacua which are not satisfied by the "Swampland" QFTs as explained by Cumrun Vafa; if we lived in the swampland, our world couldn't be described by anything inside the landscape of string theory; the generic predictions of string theory probably include the fact that gravity is the weakest force, moduli spaces have finite volume, and similar predictions that seem to be satisfied so farBy mapping the whole landscape, calculating the accurate predictions of each vacuum for the particle physics (masses, couplings, mixings), and by showing that none of them is compatible with the experimentally measured parameters of particle physics within the known error margins; this route to disprove string theory is hard but possible in principle, too (although the full mathematical machinery to calculate the properties of any vacuum at any accuracy isn't quite available today, even in principle)By analyzing physics experimentally up to the Planck scale and showing that our world contains neither supersymmetry nor extra dimensions at any scale. If you check that there is no SUSY up to a certain higher scale, you will increase the probability that string theory is not relevant for our Universe but it won't be a full proofA convincing observation of varying fundamental constants such as the fine-structure constant would disprove string theory unless some other unlikely predictions of some string models that allow such a variability would be observed at the same time

A Gravitational Explanation for Quantum Mechanics: There is no quantum theory of gravity. There is no graviton. Gravitational waves cannot exhibit quantum phenomena such as wave particle duality. Gravitational waves are not quantized. String theory is known to be inherently fuzzy already, i.e. leading to vast landscape of false vacui solutions. But string theory is quantum gravity theory and it can be proven, the same fuzziness is inherent obstacle for any other quantum gravity theory due the insintric inconsistency of postulated of both theories. Of course these insights were and will be ignored, because physical theorists are looking for ways, how to prolonge their research and how get as much grants for it as possible - not how to get their work nonsensical and ending prematurely. Quantum gravity theorists aren't an exception. We are living in era of physics driven with occupation criterions.

Try to focus to the fact, that all ways, which Motl proposes for falsification of string theory are related to string theory postulates (extradimensions, Lorentz symmetry) - not the predictions, because string theory has no testable predictions, because it actually cannot have none. For example, Motl writes, that the violation of Lorentz symmetry could disprove the string theory, because the Lorentz symmetry is one of main postulates of string theory. But the extradimensions are often searched with search of nonzero photon mass (it would make the EM finite scope interaction) - but just this nonzero photon mass would violate the Lorentz symmetry too. In another words, you cannot prove one postulate of string theory without violation of another one. Which indicates, whole this theory is deeply inconsistent by its very definition: the poor string theorists did choose a mutually inconsistent postulate set by accident.

Here is a paper which explains how Lorentz symmetry is only violated by 5d space or higher. Actually the Lorentz symmetry is violated even at the three dimensions with four dimension of space-time. The common gravitational lensing is the evidence of space-time curved and it allows to spread the light along multiple paths with different speed. It's nice example of multiverse/many worlds of quantum mechanics too.

Lubos Motl (http://motls.blogspot.cz/2006/10/falsifiability-in-physics.html) writes: "If string theory is correct, the superposition principle of quantum mechanics, Lorentz invariance, unitarity, crossing symmetry, equivalence principle etc. are valid to much higher accuracy than the accuracy with which they have been tested as of 2006." Matt Strassler (http://profmattstrassler.com/2013/09/23/quantum-field-theory-string-theory-and-predictions/): "string theory does *not* predict practically-measurable violations of the equivalence principle, and yet string theory does not forbid measurable violations of the equivalence principle ... So if we saw such violations in data, we’d have no idea what they meant, and we’d have a lot of work to do".

Absence of Unruh effect in polymer quantization LQG deals with diffeomorphism invariant states, both spatial and timelike. So, an LQG state would be in a superposition over all possible coordinate systems, including Cartesian and Rindler plus a whole lot of other coordinate systems. You just can't fix the coordinate system in LQG.